Method of and apparatus for testing paint.



A. M. MUGKENFUSS. METHOD OF AND APPARATUS FOR TESTING PAINT. A1PLIOATION FILED JULY30, 1909.

Patented'Jan. 16, 1912.

2 SHEETSSHEBT 1.

3] woe M06 71:. m Mattozme a M W COLUMBIA PLANOGRAPII co., WASHINGTON,D. c.

A. M. MUCKENFUSS. METHOD OF AND APPARATUS FOR TESTING PAINT. APPLIOATIONFILED JULY 30, 1909.

1,014,842, v PatentedJan.16,1912.

2 SHEETS-SHEET 2.

ANTHONY M. MUCKENFUSS, ,0]? UNIVERSITY, MISSISSIPPI.

METHOD OF AND APPARATUS FOR TESTING PAINT.

Specification of Letters Patent.

Application filed July 30, 1909.

Patented Jan. 16,1912.

Serial No. 510,439.

To all whom it may-concern:

Be it known that I, ANTHONY M. MUoK- ENFUSS, a citizen of the UnitedStates, residing at University, in the State of Mississippi, haveinvented certain new and useful Improvements in Methods of and Apparatusfor Testing Paint, of which the following is a full, clear, and exactdescription.

This invention relates to a method of and apparatus for testing paint.

Considered in its aspects as a method the present invention consists insubjecting a painted porous diaphragm to water or other vapor on oneside thereof, and maintaining dry air within a hermetically sealedinclosure into which a perfectly definite and measured area of the otherside of said diaphragm is exposed. The moisture taken up by the dry airis thereupon collected and weighed and corresponds of course to theamount passing through. the painted porous diaphragm. Substantially thesame procedure as above may be employed for determining the adhesion ofthe paintto the diaphragm, and I therefore desire to also include thelatter purpose within the scope of the method of this invention.

Considered in its aspects as an apparatus the present invention consistsin a frame having an opening across which a porous diaphragm is adaptedto be stretched, and means cooperating with said frame for providing apair of sealed cavities or chambers into which opposite sides of saiddiaphragm are exposed throughout their entire area. In practice, I makeuse of a mercury seal which has the double advantage of being absolutelyhernietical as a seal, besides being removable and replaceable for anynumber of repeated tests roviding for the latter under identicalconditions at each repetition. This seal is also cheap and simple toconstruct.

My invention further consists in the features of construction andcombination as hereinafter set forth and claimed.

In the drawings: Figure 1 is a vertical sectional View of a painttesting apparatus embodying the principles of my invention. Fig, 2 is aplan view of the same partly broken away. Fig. 3 is a vertical sectionalview showing a modification. Fig. 4. is a view, partly in section,showing the general arrangement of the paint testing appliance inconnection with one form of apparatus suitable for use in connectiontherewith when determining the amount of vapor passed through the paintfilm.

Referring to the drawings in which like parts are designated by the samereference sign, 1 denotes a base which I preferably make of cast-ironhaving a circumferential flange or rim 2 and a second flange or interiorrim 3 concentric with and separated from the outside rim by a narrowtrough or channel 4.

5 denotes a central cavity or basin of the base bounded by the rim 3.

6 designates a hoop or frame having a large central opening across whicha porous diaphragm 7 is adapted to be stretched. Any desired means maybe employed for clamping the diaphragm to the hoop 6, for example,another concentric hoop or band. I have shown for the purposes ofillustration, an annular ring or plate 8 adapted to be riveted or boltedto an internally extending flange 9 of the hoop 6.

10 denotes a cover of shallow cup-shaped form with a peripheraldepending edge 11. The edge 11 and the hoop 6 are both adapted tosimultaneously enter the trough or channel 4 of the base, the latterbeing concentrically contained within the former, and separatedtherefrom by a short distance. This distance and the disposition of thehoop 6 and edge 11 within the trough 4 are such that when said trough isfilled with mercury, it establishes a perfect seal. Pins 13 may beprovided to maintain the parts properly located in said trough andprevent the seal from being broken by reverse capilarity, which mightdisplace the mercury from proper sealing relation in case a sufficientdistance was not provided between the hoop 6 and the edge 11.

15 denote pipes projecting upwardly from the base 1 into the centralcavity 5 thereof and which serve as vents to maintain a proper airpressure. It is evident that any desired gas or vapor can be suppliedthrough these pipes.

16, 17, respectively denote inlet and discharge pipes at diametricallyopposite points of the cover 10. A current of dry air is intended topass through these pipes, in which case it of course traverses thechamber within the cover 10, this chamber having eX- posed therein the'upper surface of the diaphragm 7. The lower surface of the diaphragm isat the same time exposed to the vapor within the cavity 5 of the base.The

respective chambers or cavities on both sides of the diaphragm aretherefore separated from one another by the mercury seal, which may beconsidered an absolutely impassable barrier for gas or vapor of anysort. Any vapor which finds its way from one chamber to another musttherefore pass through the diaphragm 7. This diaphragm is of closelywoven fabric or other porous substance and is painted with the paint forwhich a test is required. The paint may be on either or both sides ofthe diaphragm. In view of the fact that the chambers or cavities on bothsides of the diaphragm are hermetically closed (except for their vent orinlet pipes which may be controlled as desired) the transfer of vaporthrough the diaphragm may be measured either by ascertaining the loss inthe inner cavity or the gain in the outer cavity, or both. Of course anyliquid or vapor or gas may be employed and under any desired conditionsof temperature or pressure. An alternative arrangement is that shown inFig. 3 in which there is no air current arranged for in the upperchamber, but merely a shelf, cage or weighing tray 18 is provided,adapted to be hermetically covered when it is desired to remove andweigh the same, and which is supplied with calcium chlorid or the likeadapted to absorb liquid vapor. The gain in weight in a definite timeshows the vapor traversing the diaphragm in this case.

Referring to Fig. ff in which is shown a set of apparatus in connectionwith one form of my novel paint testing appliance, an aspirator bottle19 is filled with a known volume of water 20. Before starting the testthe bottle is completely filled with water by attaching a hose to thespout adjacent the stop cock 21, cock 22 being open and cock 23 beingclosed. Then all cocks are closed and when the test begins cock 23 isopened fully and cock 21 is opened sutliciently to drop water out at aknown rate. This draws v an equivalent volume of air in the direction ofthe arrows, successively through the several parts of the apparatus. Aspout reaching from cock 23 is connected by means of a flexible tube 24to a U-shaped tube 25, which in turn is connected to a similar tube 26,preferably by means of a flexible tube 27. Tubes 25 and 26 are filledwith a suitable absorbent material in lumps so as to offer noappreciable resistance to the passage of the air through said tubes.This material may be, for example, calcium chlorid. Tube 28 is in turnconnected by means of flexible tube 29 to the apparatus shown in Fig. 1by means of the short tubular extension 16 thereof; whilecorrespondingly the oppositely disposed short tube 17 is connected bymeans of the flexible tube 30 with a conduit or tube 31 which extendslaterally from the bottom of a jar 32. This latter is also filled withlump absorbent material 33, preferably of the same chemical compositionas that used in tubes 25 and 26. The upper outlet of the jar, and thelower outlet thereof, as also the respective inlets and outlets of thetubes 25 and 26, are plugged with cotton 34L, or the like, to preventthe passage of dust through the apparatus. Preparatory to weighing thetubes 25 and 26, the flexible tubes 24 and 29, and if desired, also tube27, are plugged with suitable plugs such as are indicated at 35 so as toprevent any evaporation of moisture or any additional absorption thereoffrom the atmosphere by the material in the tubes. In operation thereforeair will be drawn successively through the jar 32, the upper chamber ofthe paint testing appliance, tubes 26 and 25, and from thence into theupper portion of the aspirator bottle, and the volume of air so passedthrough the paint testing apparatus may be accurately ascertained.

The use of the apparatus and the method of the invention will beunderstood from the foregoing description. The diaphragm is merelypainted-on one or both sides, and tested, then perhaps allowed to dry orbe subjected to the weather or exposure, if desired, for either a shortor protracted period and again tested. For the purpose of the test thetrough l is filled with mercury and the hoop 6 with its diaphragm 7placed in position. Before this the cavity 5 is supplied with water inmeasured quantity, if desired, and the vapor from this water passesthrough the paint slowly by virtue of the porosity thereof. The amountof water vapor passing is evidently proportionate to the permeability ofthe paint used. The vapor which traverses the paint is all collected inthe outer chamber and carried away by the current of dry air therein.All this vapor may subsequently be collected from the air and measured,by calcium chlorid or some equivalent means; many of which are commonlyknown.

It will be particularly observed that inasmuch as the diaphragm isstretched across a hoop and subsequently painted, that the paintedsurface is never afterward wrinkled or compressed or in any waysubjected to strains or pressure or rough handling or treatment whichmight vitiate the test and make it unlike the conditions where paint isapplied to a solid surface such as a wall or dwelling. Secondly, thesurface of the paint exposed corresponds exactly to the area of thediaphragm, and this area is exact and predetermined in all cases.Thirdly, two chambers are formed on opposite sides of the diaphragm andboth of these are absolutely hermetically sealed, the innerone beingparticularly adapted to receive a liquid and the outer to receive an aircurrent, in accordance with the method specified, a1-

though these particular uses are not essential. Fourth, the temperatureand barometric conditions are equalized on both sides of the diaphragmso that no correction is ever required by virtue of variation in thesefactors. And finally the nature of the ap paratus is such that itscomponent parts are removable and replaceable whenever desired, andadapted to give any number of easily arranged for tests, under identicalconditions at each repetition. With this simple apparatus difierentpaints, varnishes and the like may be accurately rated in matters oftheir values from the standpoints of 5 porosity and adhesive power anddurability.

The greatest value of the foregoing apparatus resides in its ability todetermine the durability .of any particular paint, or the relativedurability of different paints,

the durability being determined by measurement of the permeability ofthe paint after different stages of exposure. For example, if twodifferent kinds of paint showed the same permeability when freshlyapplied,

and showed differing permeability after a period of exposure to climaticor other conditions, it is evident that the paint showing the leastpermeability at the second test is the more durable, and in proportionto the degree that its permeability remains unchanged.

In making the test according to Fig. 3, the time or duration of the testis the factor which it is necessary to establish and con- 85 trol,instead of measuring a quantity of air supplied as is the case wit-hFigs. 1 and 2. With a paint of given permeability the amount of vaporpassing from the lower to the upper chamber is proportional to the timeor interval occupied by the test, so that the measure of this time andthe measure of the vapor absorbed by the substance in the tray 18 arethe only data required; the area and thickness of the diaphragm beingthe same.

What I claim, is

1. A method of testing paint or the like which comprises forming a filmof the sub- ,stance to be tested, exposing one side of said film to amass of vapor capable of passing through the pores of said film,permitting said vapor to pass through said pores for a substantiallydefinite period, absorbing the vapor which thus passes through said filmby absorptive material, and measuring the quantity of the vapor soabsorbed.

2. A method of testing paint which consists in exposing a porousdiaphragm coated with the paint to be tested within a chamber or cavitycontaining water vapor on one side of said diaphragm, simultaneouslyexposing the other side of the diaphragm within a second closed chamberor cavity absorbing substantially all of the vapor which may passthrough said diaphragm by a vapor absorbing medium, and

finally determining the weight of vapor so absorbed in a given intervalof time.

3. A method of testing paint or the like which comprises forming a filmof the substance to be tested, exposing one side of said film to aqueousvapor, permitting said vapor to pass through said pores for asubstantially definite period, absorbing the vapor which thus passesthrough said film by absorptive material capable of absorbing aqueousvapor, and measuring the quantity of aqueous vapor as absorbed.

4:. In an apparatus for testing paint, a porous diaphragm adapted to becoated with the paint to be tested, means cooperating with saiddiaphragm to establish a chamber or cavity on one side thereof adaptedto hold vapor, means also cooperating with the diaphragm to establish asecond closed chamber or cavity on the other side of said diaphragm alsoadapted to hold vapor, and means for accurately determining the amountof vapor which traverses the diaphragm from the first to the secondchamber mentioned,

said means comprising vapor collecting maamount of the vapor whichtraverses the diaphragm from the first to the second chamber mentioned,said means comprising vapor collecting material.

6. In an apparatus for testing paint, a po rous diaphragm adapted to becoated with the paint to be tested, means for establishing a pair ofchambers or cavities on either side of the diaphragm hermetically sealedfrom one another, each adapted to hold vapor and means for determiningthe amount of the vapor which traverses the diaphragm between therespective chambers, said means comprising vapor collecting material.

7 In an apparatus for testing paint, a porous diaphragm adapted to becoated with the paint to be tested, means removable and replaceable withrespect to said diaphragm for establishing a pair of hermetically sealedchambers on either side thereof, each adapted to hold vapor and meansfor determining the amount of the vapor which traverses the diaphragmfrom the first to the second chamber mentioned, said means comprisingvapor collecting material.

8. In an apparatus for testing paint, a porous diaphragm adapted to becoated with the paint to be tested, means including a liquid seal andcooperating with said diaphragm to establish a pair of chambers orcavities on either side thereof hermetically sealed from. one another,and each adapted to hold vapor and means for determining the amount ofthe vapor which traverses the diaphragm from the first to the secondchamber mentioned, said means comprising vapor collecting material.

9. In an apparatus for testing paint, a porous diaphragm adapted to becoated with the paint to be tested, a hoop for supporting saiddiaphragm, a base having a trough or channel, a cap having a dependingcircumferential edge, and a liquid seal in said trough or channel, saidedge and said hoop bein adapted to enter said channel concentrically oneWithin another.

10. In an apparatus for testing paint, a porous diaphragm adapted to becoated with the paint to be tested, a hoop for supporting saiddiaphragm, a base having a trough or channel and having an interiorcavity adapted to contain water, a cap having a dependingcircumferential edge, said edge and said hoop fitting in said channelconcentrically within one another, a liquid seal in said channel, andmeans for obtaining a measurement of the vapor which traverses thediaphragm from the inner to the outer chamber formed.

11. A method of testing paint which consists in exposing a porousdiaphragm coated with the paint to be tested within the chamher orcavity containing vapor on one side of said diaphragm, simultaneouslyexposing the other side of the diaphragm within a second completelyclosed chamber or cavity containing a substance adapted to absorb thevapor, and measuring the weight of vapor absorbed by said substance in agiven time interval.

12. In an apparatus for testing paint, a porous diaphragm adapted to bepainted with the paint to be tested, means cooperating with saiddiaphragm to establish a chamber or cavity on one side thereof, meansalso cooperating with the diaphragm to establish a second completelyclosed chamber or cavity onthe other side of said diaphragm, and a cageor tray in said second chamber or cavity for containing a vaporabsorbing substance.

In witness whereof, I subscribe my signature, in the presence of twoWitnesses.

ANTHONY M. MUOKENFUSS.

Witnesses:

ALFRED WV. PRooToR, WALDO M. OHAPIN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

